Flow Analysis in Polymer Processing of Fiber Reinforced liquid Crystalline Polymers

在这项工作中，我们分析了纤维增强液晶聚合物(LCP)在聚合物加工过程中的速度场和分子取向。采用TIF模型和DOI模型对液晶盒在模型几何结构中的流动进行了数值模拟；平行平板包括圆柱和圆柱阵列。用羟丙基纤维素(HPC)溶液进行了实验研究。本工作取得的成果如下：1。利用TIF模型和DOI模型，得到了平行平板间的分子取向分布。结果表明，在LCP与纤维之间的流动中，应特别注意冷凝器后面的焊缝的产生。在TIF模型的模拟中，发现圆柱阵列几何结构中的发散和收敛流动对分子的取向有很大的影响。在液晶平板间纤维悬浮液的径向流动实验中，发现液晶相中纤维取向的有序参数小于各向同性相中的有序参数。结果表明，HPC溶液液晶相速度场的微观不均匀性是其原因之一。

In this work we analyzed the velocity fields and the molecular orientations in the polymer processing of fiber reinforced liquid crystalline polymers (LCPs) which had both reinforcements by fiber orientation and molecular one. The TIF model and the Doi model are applied to the numerical simulations of the flows of LCPs in the model geometries ; parallel plates containing a cylinder and cylinder arrays. The experimental investigations are also performed by using the solutions of hydroxypropylcellulose (HPC). Results obtained in this work are as follows1. The distribution of molecular alignment in the flow between parallel plates containing a crylinder is obtained by using the TIF model and the Doi model. From the result it is showed that a special attention should be paied to the occurrence of weld behind the crylinder in the flow of LCPs beteen fibers.2. In the simulation by the TIF model it becomes clear the molecular alignment is largely affected by diverging and converging flows in the cylinder array geometries.3. In the experiment of the radial flow of fiber susupensions in LCPs between circular parallel paltes, it is found that order parameter of fiber orientation in liquid crystal phases is less than that in isotropic phase. It is suggested that micro inhomogeneity in a velocity field in the liquid crystal phase of HPC solutions is one of this reason.